Submission #965386

#	Time	Username	Problem	Language	Result	Execution time	Memory
965386		akacool445k	Arranging Shoes (IOI19_shoes)	C++14	10 / 100	1 ms	504 KiB

shoes

#include <queue>
#include <iostream>
#include "shoes.h"

using namespace std;

int N;
int bit[200001];
int query(int i) {
	int res = 0;
	while (i > 0) {
		res += bit[i];
		i -= (i & -i);
	}
	return res;
}
void update(int i) {
	while (i <= N) {
		bit[i] = 0;
		i += (i & -i);
	}
}

long long count_swaps(vector<int> s) {
	long long n = s.size();
	long long ans = 0;
	N = n;
	queue<int> a[n / 2 + 1], b[n / 2 + 1];
	for (int i = 0; i < n; i++) {
		if (s[i] < 0) a[-s[i]].push(i);
		else b[s[i]].push(i);
	}

	vector<int> c(n, 1);
	for (int i = 0; i < n; i++) {
		if (c[i] == 0) continue;
		int ss = 0;
		int x = s[i];
		int j = i;
		if (x < 0) {
			int y = -x;
			j = b[y].front();
			b[y].pop();
			a[y].pop();
		} else {
			j = a[x].front();
			a[x].pop();
			b[x].pop();
		}
		update(i + 1);
		update(j + 1);
		ans += query(j + 1);
		c[j] = 0;
		if (x > 0) ans++;
	}
	return ans;
}

Compilation message (stderr)

shoes.cpp: In function 'long long int count_swaps(std::vector<int>)':
shoes.cpp:38:7: warning: unused variable 'ss' [-Wunused-variable]
   38 |   int ss = 0;
      |       ^~

• Subtask 1: 10 / 10
• Subtask 2: 0 / 20
• Subtask 3: 0 / 20
• Subtask 4: 0 / 15
• Subtask 5: 0 / 20
• Subtask 6: 0 / 15